[RASMB] time to reach equilibrium

[James Cole]

Dear Patrick:
There is a nice systematic approach to monitor the approach to equilibrium.
The program WINMATCH is designed to test whether equilibrium has been
reached. It does a least-squares comparison of the sequential scans and
allows for (random) displacements in the vertical and horizontal directions.
If you are at equilibrium, the RMS deviations decrease as a function of time
until they reach a constant level corresponding to the noise level in the
data. WINMATCH is particular useful with  interference optics  due to the
high precision of the data.

Sincerely,
Jim Cole
***********************************************
James Cole
Department of Molecular and Cell Biology
National Analytical Ultracentrifugation Facility
University of Connecticut
91 North Eagleville Road, U-3125
Storrs, CT 06269-3125, USA
Tel.:   (860) 486-4333
FAX:  (860) 486-4331
E-mail: james.cole at uconn.edu <mailto:james.cole at uconn.edu>



***********************************************



-----Original Message-----
From: rasmb-admin at rasmb-email.bbri.org
[mailto:rasmb-admin at rasmb-email.bbri.org]On Behalf Of Patrick England
Sent: Wednesday, June 04, 2003 7:59 AM
To: rasmb at rasmb-email.bbri.org
Subject: [RASMB] time to reach equilibrium


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Dear RASMB mailing list members,

A general question regarding sedimentation/diffusion equilibria...
What is, in your experience, the most effective way to determine and/or
predict the time needed for the equilibrium to be reached at a given rotor
speed?
In practice, do you consider that the equilibrium is attained when no
change can be observed in the concentration boundary for a certain length
of time, or when the equilibrium is theoretically reached with a certain
confidence interval?

Many thanks for your replies!

Sincerely yours,
Patrick England

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Patrick ENGLAND

Responsable de la Plate-forme de Biophysique des Macromolécules et de leurs
Interactions,
Département de Biologie Structurale et Chimie,
Institut Pasteur,
28, rue du Docteur Roux,
75724 Paris Cedex 15, France

tel: (33-1) 45.68.83.83
fax: (33-1) 40.61.30.43
e-mail: biophysique at pasteur.fr


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